Family, twin, and adoption studies of bipolar disorder

Risk for bipolar disorder is associated with face-processing deficits across emotions

OBJECTIVE

Youths with euthymic bipolar disorder (BD) have a deficit in face-emotion labeling that is present across multiple emotions. Recent research indicates that youths at familial risk for BD, but without a history of mood disorder, also have a deficit in face-emotion labeling, suggesting that such impairments may be an endophenotype for BD. It is unclear whether this deficit in at-risk youths is present across all emotions or if the impairment presents initially as an emotion-specific dysfunction that then generalizes to other emotions as the symptoms of BD become manifest.

METHOD

Thirty-seven patients with pediatric BD, 25 unaffected children with a first-degree relative with BD, and 36 typically developing youths were administered the Emotional Expression Multimorph Task, a computerized behavioral task, which presents gradations of facial emotions from 100% neutrality to 100% emotional expression (happiness, surprise, fear, sadness, anger, and disgust).

RESULTS

Repeated-measures analysis of covariance revealed that, compared with the control youths, the patients and the at-risk youths required significantly more intense emotional information to identify and correctly label face emotions. The patients with BD and the at-risk youths did not differ from each other. Group-by-emotion interactions were not significant, indicating that the group effects did not differ based on the facial emotion.

CONCLUSIONS

The youths at risk for BD demonstrate nonspecific deficits in face-emotion recognition, similar to patients with the illness. Further research is needed to determine whether such deficits meet all the criteria for an endophenotype.

Substance abuse and hospitalization for mood disorder among Medicaid beneficiaries

OBJECTIVES

We compared the influence of substance abuse with that of other comorbidities (e.g., anxiety, HIV) among people with mood disorder (N=129,524) to explore risk factors for psychiatric hospitalization and early readmission within 3 months of discharge.

METHODS

After linking Medicaid claims data in 5 states (California, Florida, New Jersey, New York, and Texas) to community-level information, we used logistic and Cox regression to examine hospitalization risk factors.

RESULTS

Twenty-four percent of beneficiaries with mood disorder were hospitalized. Of these, 24% were rehospitalized after discharge. Those with comorbid substance abuse accounted for 36% of all baseline hospitalizations and half of all readmissions.

CONCLUSIONS

Results highlight the need for increased and sustained funding for the treatment of comorbid substance abuse and mood disorder, and for enhanced partnership between mental health and substance abuse professionals.

Evaluation of tissue collection for postmortem studies of bipolar disorder

OBJECTIVES

Postmortem human brain is a valuable resource for studying the neuropathology, neurochemistry, and molecular pathways of genes associated with bipolar disorder (BPD), yet available, well-characterized BPD brain tissue appears scarce. We set out to evaluate BPD postmortem brain collections in order to identify both successful methods as well as barriers to collection.

METHODS

We conducted a literature review of postmortem studies of BPD over the past 30 years, compared and contrasted characteristics of established BPD collections, and identified possible barriers specific to BPD brain collection based on our experience at the NIMH Brain Collection.

RESULTS

Currently, 80% of postmortem BPD studies were derived from just two brain repositories worldwide: the Stanley Brain Collection (69%) and Harvard Brain Tissue Resource Center (HBTRC) (11%) (combined subjects n = 72). The NIMH Brain Collection collected BPD cases four times less frequently than cases with schizophrenia, despite similar prevalence rates for these disorders. Only 53% of cases referred to the NIMH collection as BPD met DSM-IV criteria, with inadequate documentation and comorbid substance abuse as primary confounds for diagnosis in the remaining 47% of cases.

CONCLUSIONS

Accurate identification and diagnosis of BPD is a central obstacle to BPD brain collection. Comorbid substance abuse and manner of death are two of many critical factors to consider in BPD postmortem studies. Difficulties in BPD brain collection, coupled with the cessation of brain collection by the Stanley Brain Collection, make the need for alternative BPD brain sources imperative. Recommendations for future BPD tissue collection are offered.

Exchangeable models of complex inherited diseases

A model of unlinked diallelic loci affecting the risk of a complex inherited disease is explored. The loci are equivalent in their effect on disease risk and are in Hardy-Weinberg and linkage equilibrium. The goal is to determine what assumptions about dependence of disease risk on genotype are consistent with data for diseases such as schizophrenia, bipolar disorder, autism, and multiple sclerosis that are relatively common (0.1-2% prevalence) and that have high concordance rates for monozygotic twins (30-50%) and high risks to first-degree relatives of affected individuals (risk ratios exceeding 4). These observations are consistent with a variety of models, including generalized additive, multiplicative, and threshold models, provided that disease risk increases rapidly for a narrow range of numbers of causative alleles. If causative alleles are in relatively high frequency, then the combined effects of numerous causative loci are necessary to substantially elevate disease risk.

A structural approach to the familial coaggregation of disorders

The demonstration that 2 disorders coaggregate in families is often the first step in the exploration of genetic factors common to the 2 disorders. Previous methods of analyzing familial coaggregation have used either (1) a typical measure of association (eg, the odds ratio) between a disorder in an individual and another disorder in family members, or (2) a linear structural equation model (SEM). The association method accommodates case-control sampling of families, but may not assess the causal effect of interest because it is not based on an underlying causal model. The SEM method is based on a causal model, but cannot easily accommodate case-control sampling or direct effects of 1 disorder on the other within individuals. We develop a new method of analyzing coaggregation based on directed acyclic graphs. Because this method is a generalization of structural equation models and uses measures of association that accommodate case-control sampling and direct effects, it combines the strengths of both previous methods. In the absence of direct effects between disorders, our approach provides a valid estimate of the causal coaggregation effect. In the presence of direct effects, our approach provides an upper-bound estimate and (assuming additive linear effects of latent familial and nonfamilial factors) a lower-bound estimate of the causal coaggregation effect. For illustration, we applied our method to a family study of binge eating disorder and bipolar disorder.

Neurophysiological endophenotypes across bipolar and schizophrenia psychosis

The search for liability genes of the world's 2 major psychotic disorders, schizophrenia and bipolar disorder I (BP-I), has been extremely difficult even though evidence suggests that both are highly heritable. This difficulty is due to the complex and multifactorial nature of these disorders. They encompass several intermediate phenotypes, some overlapping across the 2 psychotic disorders that jointly and/or interactively produce the clinical manifestations. Research of the past few decades has identified several neurophysiological deficits in schizophrenia that frequently occur before the onset of psychosis. These include abnormalities in smooth pursuit eye movements, P50 sensory gating, prepulse inhibition, P300, mismatch negativity, and neural synchrony. Evidence suggests that many of these physiological deficits are distinct from each other. They are stable, mostly independent of symptom state and medications (with some exceptions) and are also observed in non-ill relatives. This suggests a familial and perhaps genetic nature. Some deficits are also observed in the BP-I probands and to a lesser extent their relatives. These deficits in physiological measures may represent the intermediate phenotypes that index small effects of genes (and/or environmental factors). The use of these measures in genetic studies may help the hunt for psychosis liability genes and clarify the extent to which the 2 major psychotic disorders share etio-pathophysiology. In spite of the rich body of work describing these neurophysiological measures in psychotic disorders, challenges remain: Many of the neurophysiological phenotypes are still relatively complex and are associated with low heritability estimates. Further refinement of these physiological phenotypes is needed that could identify specific underlying physiological deficits and thereby improve their heritability estimates. The extent to which these neurophysiological deficits are unique or overlap across BP-I and schizophrenia is unclear. And finally, the clinical and functional consequences of the neurophysiological deficits both in the probands and their relatives are not well described.

The proximal prodrome to first episode mania--a new target for early intervention

OBJECTIVE

Affective psychoses and bipolar disorders have been neglected in the development of early intervention strategies. This paper aims to gather current knowledge on the early phase of bipolar disorders in order to define new targets for early intervention.

METHODS

Literature review based on the main computerized databases (MEDLINE, PUBMED and PSYCHLIT) and hand search of relevant literature.

RESULTS

Based on current knowledge, it is likely that an approach aiming at the identification of impending first-episode mania is the most realistic and manageable strategy to promote earlier treatment. During the period preceding the onset of the first manic episode, patients go through a prodromal phase marked by the presence of mood fluctuation, sleep disturbance, and other symptoms such as irritability, anger, or functional impairment. Additionally, various risk factors and markers of vulnerability to bipolar disorders have been identified.

CONCLUSIONS

In the few months preceding first-episode mania, patients go through a prodrome phase (proximal prodrome) that could become an important target for early intervention. However, considering the low specificity of the symptoms observed during this phase, criteria defining high-risk profiles to first-episode mania should also include certain risk factors or markers of vulnerability. While more research is needed in high-risk groups (e.g., bipolar offspring), retrospective studies conducted in first-episode mania cohorts could provide valuable information about this critical phase of the illness.

Whole-genome association study of bipolar disorder

We performed a genome-wide association scan in 1461 patients with bipolar (BP) 1 disorder, 2008 controls drawn from the Systematic Treatment Enhancement Program for Bipolar Disorder and the University College London sample collections with successful genotyping for 372,193 single nucleotide polymorphisms (SNPs). Our strongest single SNP results are found in myosin5B (MYO5B; P=1.66 x 10(-7)) and tetraspanin-8 (TSPAN8; P=6.11 x 10(-7)). Haplotype analysis further supported single SNP results highlighting MYO5B, TSPAN8 and the epidermal growth factor receptor (MYO5B; P=2.04 x 10(-8), TSPAN8; P=7.57 x 10(-7) and EGFR; P=8.36 x 10(-8)). For replication, we genotyped 304 SNPs in family-based NIMH samples (n=409 trios) and University of Edinburgh case-control samples (n=365 cases, 351 controls) that did not provide independent replication after correction for multiple testing. A comparison of our strongest associations with the genome-wide scan of 1868 patients with BP disorder and 2938 controls who completed the scan as part of the Wellcome Trust Case-Control Consortium indicates concordant signals for SNPs within the voltage-dependent calcium channel, L-type, alpha 1C subunit (CACNA1C) gene. Given the heritability of BP disorder, the lack of agreement between studies emphasizes that susceptibility alleles are likely to be modest in effect size and require even larger samples for detection.

Chromosome 10q harbors a susceptibility locus for bipolar disorder in Ashkenazi Jewish families

We report the results of a 10 cM density genome-wide scan and further fine mapping of three chromosomal candidate regions in 10 Belgian multigenerational families with bipolar (BP) disorder. This two-stage approach revealed significant evidence for linkage on chromosome 10q21.3-10q22.3, showing a maximum multipoint parametric heterogeneity logarithm of odds (HLOD) score of 3.28 and a nonparametric linkage (NPL) score of 4.00. Most of the chromosome 10q evidence was derived from a single, large Ashkenazi Jewish pedigree. Haplotype analysis in this pedigree shows that the patients share a 14-marker haplotype, defining a chromosomal candidate region of 19.2 cM. This region was reported previously as a candidate region for BP disorder in several independent linkage analysis studies and in one large meta-analysis. It was also implicated in a linkage study on schizophrenia (SZ) in Ashkenazi Jewish families. Additionally, we found suggestive evidence for linkage on chromosome 19q13.2-13.4 (HLOD 2.01, NPL 1.09) and chromosome 7q21-q22 (HLOD 1.45, NPL 2.28). Together, these observations suggest that a gene located on chromosome 10q21.3-10q22.3 is underlying the susceptibility both for SZ and for BP disorder in at least the Ashkenazi Jewish population.

Volumetric neuroimaging investigations in mood disorders: bipolar disorder versus major depressive disorder

BACKGROUND

As patients with mood disorders manifest heterogeneity in phenomenology, pathophysiology, etiology, and treatment response, a biological classification of mental disease is urgently needed to advance research. Patient and methodological variability complicates the comparison of neuroimaging study results and limits heuristic model development and a biologically-based diagnostic schema.

OBJECTIVE

We have critically reviewed and compared the magnetic resonance neuroimaging literature to determine the degree and directionality of volumetric changes in brain regions putatively implicated in the pathophysiology of major depressive disorder (MDD) versus bipolar disorder (BD).

METHODS

A total of 140 published magnetic resonance imaging investigations evaluating subjects with BD or MDD were selected to provide a summary and interpretation of volumetric neuroimaging results in MDD and BD. Further commentary on the pathophysiological implications, and putative cellular and pharmacological mechanisms, is also provided.

RESULTS

While whole brain volumes of patients with mood disorders do not differ from those of healthy controls, regional deficits in the frontal lobe, particularly in the anterior cingulate and the orbitofrontal cortex, appear to consistently differentiate subjects with mood disorders from the general population. Preliminary findings also suggest that subcortical structures, particularly the striatum, amygdala, and hippocampus, may be differentially affected in MDD and BD.

CONCLUSIONS

Structural neuroimaging studies have consistently identified regional abnormalities in subjects with mood disorders. Future studies should strive to definitively establish the influence of age and medication.

Stage II follow-up on a linkage scan for bipolar disorder in the Ashkenazim provides suggestive evidence for chromosome 12p and the GRIN2B gene

PURPOSE

We had previously performed a genome-wide linkage scan for bipolar affective disorder in an Ashkenazi Jewish sample, a population likely to have reduced genetic heterogeneity. This study is a second stage follow-up focusing on regions that showed positive linkage scores in our previous scan but were not fine-mapped at that time.

METHODS

We genotyped an additional 145 highly polymorphic microsatellites and conducted linkage analyses using standard laboratory and analytical methods.

RESULTS

We saw an improvement of the evidence for linkage in most regions, with the most notable change on chromosome 12p13.1-p12.3, where the evidence of linkage is now suggestive. This region harbors the gene encoding the ionotropic glutamate receptor subunit 2B (GRIN2B), a gene that previously yielded evidence for association in a candidate gene study on 323 Ashkenazi Jewish bipolar case-parent trios. We find that the evidence for linkage is significantly correlated with the presence of the putative high-risk allele identified in our candidate gene study.

CONCLUSIONS

Following up weaker signals can significantly improve linkage signals even after relatively small increases in information content. Our results on chromosome 12p support GRIN2B as a candidate gene for bipolar disorder that needs further investigation.

Familiality and diagnostic patterns of subphenotypes in the National Institutes of Mental Health bipolar sample

Bipolar-related subphenotypes that cluster within families may help identify subsets of patients that are more genetically homogeneous. Environmental or assessment factors that segregate by family may influence estimates of familiality. We aimed to determine familiality of subphenotypes of bipolar disorder (BP), accounting for effects of age, sex, diagnosis, and site/wave of ascertainment. We studied 589 sibships with 1416 siblings affected with bipolar I (BPI), schizoaffective disorder, bipolar type (SAB), bipolar II (BPII), or recurrent unipolar depression (RUDD). Sibships were from families with > or =2 BPI cases collected by the NIMH Bipolar Genetics Initiative (NIMHBGI). Rapid cycling showed the strongest evidence for familiality [odds ratio (OR) (95%CI) = 2.02 (1.43, 2.85), P = 6.0 x 10(-5)] in a model including age, sex, diagnosis, and site/wave of ascertainment. Additional significantly familial traits were comorbid alcohol abuse/dependence (P = 2 x 10(-4)) and comorbid panic disorder (P = 8 x 10(-3)), as well as psychosis, suicidal thoughts, and rapid mood switching (P = 6 x 10(-3) - 0.03). Omission of the effect of site/wave of ascertainment from the model inflated the significance level of the apparent familial association of almost all subphenotypes from one to four orders of magnitude. We have found evidence of familiality for subphenotypes of BP. In multicenter samples, familiality may be overestimated if variability in diagnosis of subphenotypes between site/wave of ascertainment is not considered.

Gene-based SNP mapping of a psychotic bipolar affective disorder linkage region on 22q12.3: association with HMG2L1 and TOM1

Genetic linkage studies in both bipolar affective disorder (BPAD) and schizophrenia have implicated overlapping regions of chromosome 22q. We previously reported that BPAD pedigrees containing multiple members with psychotic symptoms showed suggestive linkage to chromosome 22q12.3. Now we have tested 189 single nucleotide polymorphisms (SNPs) spanning a 3 Mb region around the linkage peak for association with BPAD in 305 families, unrelated cases, and controls. SNPs were selected in or near genes, resulting in coverage at a density of 1 SNP per 6.7 kb across the 22 annotated genes in the region. The strongest signal emerged from family-based association analysis of an 11-SNP, 54 kb haplotype straddling the gene HMG2L1 and part of TOM1. A 3-marker haplotype of SNPs within TOM1 was associated with BPAD (allele-wise P = 0.0011) and with psychotic BPAD (allele-wise P = 0.00049). As hypothesized, the mean odds ratio for the risk alleles across the region was 1.39 in the psychotic but only 0.96 in the non-psychotic subset. Genotype-wise analyses yielded similar results, but the psychotic/non-psychotic distinction was more pronounced with mean odds ratios of 1.91 versus 0.8. Permutation of genotype-wise results for rs2413338 in HMG2L1 showed an empirical P = 0.037 for the difference between subsets. HMG2L1 is a negative regulator of Wnt signaling, a pathway of interest in psychotic BPAD as it is activated by both mood stabilizer and anti-psychotic medications. Further work is needed to confirm these results and uncover the functional variation underlying the association signal.

Prevention of bipolar disorder in at-risk children: theoretical assumptions and empirical foundations

This article examines how bipolar symptoms emerge during development, and the potential role of psychosocial and pharmacological interventions in the prevention of the onset of the disorder. Early signs of bipolarity can be observed among children of bipolar parents and often take the form of subsyndromal presentations (e.g., mood lability, episodic elation or irritability, depression, inattention, and psychosocial impairment). However, many of these early presentations are diagnostically nonspecific. The few studies that have followed at-risk youth into adulthood find developmental discontinuities from childhood to adulthood. Biological markers (e.g., amygdalar volume) may ultimately increase our accuracy in identifying children who later develop bipolar I disorder, but few such markers have been identified. Stress, in the form of childhood adversity or highly conflictual families, is not a diagnostically specific causal agent but does place genetically and biologically vulnerable individuals at risk for a more pernicious course of illness. A preventative family-focused treatment for children with (a) at least one first-degree relative with bipolar disorder and (b) subsyndromal signs of bipolar disorder is described. This model attempts to address the multiple interactions of psychosocial and biological risk factors in the onset and course of bipolar disorder.

A possible association between missense polymorphism of the breakpoint cluster region gene and lithium prophylaxis in bipolar disorder

Lithium is one of the most commonly used drugs for the treatment of bipolar disorder. To prescribe lithium appropriately to patients, predictors of response to this drug were explored, and several genetic markers are considered to be good candidates. We previously reported a significant association between genetic variations in the breakpoint cluster region (BCR) gene and bipolar disorder. In this study, we examined a possible relationship between response to maintenance treatment of lithium and Asn796Ser single-nucleotide polymorphism in the BCR gene. Genotyping was performed in 161 bipolar patients who had been taking lithium for at least 1 year, and they were classified into responders for lithium mono-therapy and non-responders. We found that the allele frequency of Ser796 was significantly higher in non-responders than in responders. Further investigation is warranted to confirm our findings.

Genetics of bipolar disorder

Family and twin studies have consistently documented that bipolar disorder (BPD) is familial and heritable, but efforts to identify specific susceptibility genes have been complicated by the disorder's genetic and phenotypic complexity. Genetic linkage studies have implicated numerous chromosomal regions, but findings have been inconsistent. As with other complex disorders, it has become clear that linkage analysis lacks the power and precision to identify susceptibility loci for BPD. Candidate gene association studies have implicated several specific genes, but these studies have been limited by our incomplete understanding of the disorder's biology, and there have been few robustly replicated results. Within the past 2 years, a major advance in the genetics of complex disease has become feasible in the form of genome-wide association studies. Such studies, which require large sample sizes, have already proven successful in identifying susceptibility variants for a range of common medical disorders. Genome-wide association studies have begun to appear for BPD, and more are in progress. By providing an unbiased approach, this technology may reveal novel biological mechanisms underlying BPD.

Setting the stage: from prodrome to treatment resistance in bipolar disorder

Bipolar disorder is common, and both difficult to detect and diagnose. Treatment is contingent on clinical needs, which differ according to phase and stage of the illness. A staging model could allow examination of the longitudinal course of the illness and the temporal impact of interventions and events. It could allow for a structured examination of the illness, which could set the stage for algorithms that are tailored to the individuals needs. A staging model could further provide as structure for assessment, gauging treatment and outcomes. The model incorporates prodromal stages and emphasizes early detection and algorithm appropriate intervention where possible. At the other end of the spectrum, the model attempts to operationalize treatment resistance. The utility of the model will need to be validated by empirical research.

Attitudes towards childbearing, causal attributions for bipolar disorder and psychological distress: a study of families with multiple cases of bipolar disorder

BACKGROUND

For families with multiple cases of bipolar disorder this study explored: attitudes towards childbearing; causal attributions for bipolar disorder, in particular the degree to which a genetic model is endorsed and its impact on the perceived stigma of bipolar disorder; and predictors of psychological distress.

METHOD

Two hundred individuals (95 unaffected and 105 affected with either bipolar disorder, schizo-affective disorder - manic type, or recurrent major disorder) were surveyed, using mailed, self-administered questionnaires.

RESULTS

Thirty-five (35%) participants reported being 'not at all willing to have children' or 'less willing to have children' as a result of having a strong family history of bipolar disorder. Being not at all or less willing to have children was associated with perceived stigma of bipolar disorder [odds ratio (OR) 2.42, p = 0.002], endorsement of a genetic model (OR 1.76, p = 0.046), and being affected (OR 2.16, p = 0.01). Among unaffected participants only, endorsement of a genetic model was strongly correlated with perceived stigma (rs = 0.30, p = 0.004). Perceiving the family environment as an important factor in causing bipolar disorder was significantly associated with psychological distress (OR 1.58, p = 0.043) among unaffected participants. Among affected participants, perceived stigma was significantly correlated with psychological distress (OR 2.44, p = 0.02), controlling for severity of symptoms (p < 0.001).

CONCLUSIONS

Having a genetic explanation for bipolar disorder may exacerbate associative stigma among unaffected members from families with multiple cases of bipolar disorder, while it does not impact on perceived stigma among affected family members. Affected family members may benefit from interventions to ameliorate the adverse effects of perceived stigma.

Bipolar disorder and epilepsy: a bidirectional relation? Neurobiological underpinnings, current hypotheses, and future research directions

A number of studies have demonstrated that affective disorders in epilepsy represent a common psychiatric comorbidity; however, most of the classic neuropsychiatric literature focuses on depression, which is actually prominent, but little is known about bipolar depression, and very little about mania, in epilepsy. Biochemical, structural, and functional abnormalities in primary bipolar disorder could also occur secondary to seizure disorders. The kindling paradigm, invoked as a model for understanding seizure disorders, has also been applied to the episodic nature of bipolar disorder. In bipolar patients, changes in second-messenger systems, such as G-proteins, phosphatidylinositol, protein kinase C, myristoylated alanine-rich C kinase substrate, or calcium activity have been described, along with changes in c-fos expression. Common mechanisms at the level of ion channels might include the antikindling and the calcium-antagonistic and potassium outward current-modulating properties of antiepileptic drugs. All these lines of research appear to be converging on a richer understanding of neurobiological underpinnings between bipolar disorder and epilepsy. Mania, which is the other side of the coin in affective disorders, may represent a privileged window into the neurobiology of mood regulation and the neurobiology of epilepsy itself. Future research on intracellular mechanisms might become decisive for a better understanding of the similarities between these two disorders.

Aggression, hostility, and irritability in children at risk for bipolar disorder

OBJECTIVES

To assess aggression, irritability and hostility in children at risk for bipolar disorder (BP).

METHODS

Using the parent and the child versions of the Children's Hostility Inventory (CHI), we assessed aggression, hostility, and irritability in 300 offspring aged 6-18 years old of BP parents and 169 children of community controls.

RESULTS

Children of BP parents have significantly higher scores on the total CHI and its subscales than do children of control parents. After adjusting for demographic variables, both parents' non-BP psychopathology, child psychopathology, and within-family correlations, three factors remain significant: total CHI by parent rating, irritability subscale by parent rating, and irritability by child self-report. The hostility subscale by parent rating became a trend.

CONCLUSIONS

Children of BP parents score higher on ratings of hostility and irritability than children of community control parents, independent of child psychopathology and non-BP parental psychopathology. Follow-up of these children to evaluate whether these symptoms are markers for the development of BP or mood disorders is warranted.

Adult bipolar disorder is continuous with pediatric bipolar disorder

Considerable debate exists regarding the continuity of bipolar disorder (BD) in children and adolescents. Do affected children continue to have BD as adults? Are pediatric forms of BD distinct from adult forms of the disorder? Here, I argue that, in fact, strictly defined BD I and II in children and adolescents is continuous with adult BD. First, if we take developmental differences into account, children and adults share similar symptoms, since they are both diagnosed according to DSM-IV criteria. Next, retrospective studies indicate that 50% to 66% of adults with BD had onset of their disorder before age 19 years. Early prospective data indicate that adolescents with BD progress to become young adults with BD. Further, family studies of pediatric BD probands find high rates of BD in adult relatives, and pediatric offspring of parents with BD have elevated rates of BD, compared with control subjects. Finally, biological characteristics of pediatric BD (such as treatment response, neurobiology, and genetics) are either shared with adults having BD or fit logically into developmental models of BD. Thus, while not conclusive, a preponderance of data support the hypothesis that pediatric BD is continuous with adult BD. Prospective studies incorporating phenomenological and biological assessment are needed to decisively address this issue.

Bipolar disorder: how far are we from a rigorous definition and effective management?

Bipolar disorder is a pathological disturbance of mood, characterized by waxing and waning manic, depressive and, sometimes distinctly mixed states. A diagnosis of bipolar disorder can only be made with certainty when the manic syndrome declares itself. Most individuals who are diagnosed with this disorder will experience both poles of the illness recurrently, but depressive episodes are the commonest cause of morbidity and, indeed, of death by suicide. Twin, adoption and epidemiological studies suggest a strongly genetic aetiology. It is a genetically and phenotypically complex disorder. Thus, the genes contributing are likely to be numerous and of small effect. Individuals with bipolar disorder also display deficits on a range of neuropsychological tasks in both the acute and euthymic phases of illness and correlations between number of affective episodes experienced and task performance are commonly reported. Current self-report and observer-rated scales are optimized for unipolar depression and hence limited in their ability to accurately assess bipolar depression. The development of a specific depression rating scale will improve the assessment of bipolar depression in both research and clinical settings. It will improve the development of better treatments and interventions. Guidelines support the use of antidepressants for bipolar depression. With regard to the adverse effects of antidepressants for bipolar depression, double-blind, placebo-controlled data suggest that antidepressant monotherapy or the addition of a tricyclic antidepressant may worsen the course of bipolar disorder. Importantly, adjunctive psychotherapies add significantly (both statistically and clinically) to the efficacy of pharmacological treatment regimens. The successful management of bipolar disorder clearly demands improved recognition of bipolar disorder and effective long-term treatment for bipolar depression as well as mania.

Chasing genes for mood disorders and schizophrenia in genetically isolated populations

Major affective disorders and schizophrenia are among the most common brain diseases worldwide and their predisposition is influenced by a complex interaction of genetic and environmental factors. So far, traditional linkage mapping studies for these complex disorders have not achieved the same success as the positional cloning of genes for Mendelian diseases. The struggle to identify susceptibility genes for complex disorders has stimulated the development of alternative approaches, including studies in genetically isolated populations. Since isolated populations are likely to have both a reduced number of genetic vulnerability factors and environmental background and are therefore considered to be more homogeneous compared to outbred populations, the use of isolated populations in genetic studies is expected to improve the chance of finding susceptibility loci and genes. Here we review the role of isolated populations, based on linkage and association studies, in the identification of susceptibility genes for bipolar disorder and schizophrenia.

Genome-wide scan supports the existence of a susceptibility locus for schizophrenia and bipolar disorder on chromosome 15q26

Schizophrenia (SZ) and bipolar disorder (BPD) are two severe psychiatric diseases with a strong genetic component. In agreement with the 'continuum theory', which suggests an overlap between these disorders, the existence of genes that affect simultaneously susceptibility to SZ and BPD has been hypothesized. In this study we performed a 7.5 cM genome scan in a sample of 16 families affected by SZ and BPD, all originating from the same northeast Italian population. Using both parametric and non-parametric analyses we identified linkage peaks on four regions (1p, 1q, 4p and 15q), which were then subjected to a follow-up study with an increased marker density. The strongest linkage was obtained on chromosome 15q26 with a non-parametric linkage of 3.05 for marker D15S1014 (nominal P=0.00197). Interestingly, evidence for linkage with the same marker has been reported previously by an independent study performed on SZ and BPD families from Quebec. In this region, the putative susceptibility gene ST8SIA2 (also known as SIAT8B) was recently associated with SZ in a Japanese sample. However, our allele frequency analyses of the two single-nucleotide polymorphisms (SNPs) with putative functional outcome (rs3759916 and rs3759914) suggest that these polymorphisms are unlikely to be directly involved in SZ in our population. In conclusion, our results support the presence of a gene in 15q26 that influences the susceptibility to both SZ and BPD.

Psychopathology in the young offspring of parents with bipolar disorder: a controlled pilot study

Studies have suggested that the offspring of parents with bipolar disorder are at risk for a spectrum of psychopathology, but few have focused on children in the youngest age ranges or examined the impact of comorbid parental disorders. We utilized a pre-existing sample of young (mean age: 6.8 years) offspring of parents with bipolar disorder (n=34), of parents with panic or major depression (n=179), and of parents with neither mood or anxiety disorder (n=95). Children were assessed blindly to parental diagnoses using the Schedule for Affective Disorders and Schizophrenia-Epidemiologic version (K-SADS-E). Offspring of bipolar parents had significantly higher rates of disruptive behavior and anxiety disorders than offspring from both of the comparison groups, accounted for by elevated rates of ADHD and overanxious disorder. These comparisons were significant even when lifetime histories of the corresponding categories of comorbid disorders in the parents (disruptive behavior disorders and anxiety disorders) were covaried. In addition, offspring of bipolar parents had increased rates of bipolar I disorder, compared with psychiatric controls. Results support the hypotheses of elevated behavior, anxiety, and mood disorders among offspring at risk for bipolar disorder, and suggest that this psychopathology is already evident in early childhood.

Evidence of linkage and association on 18p11.2 for psychosis

The genetic basis of bipolar disorder (BPD) and schizophrenia (SCZ) has been established through numerous clinical and molecular studies. Although often considered separate nosological entities, evidence now suggests that the two syndromes may share some genetic liability. Recent studies have used a composite phenotype (psychosis) that includes BPD, SCZ, psychosis not otherwise specified, and schizoaffective disorder, to identify shared susceptibility loci. Several chromosomal regions are reported to be shared between these syndromes (18p, 6q, 10p, 13q, 22q). As a part of our endeavor to scan these regions, we report a positive linkage and association finding at 18p11.2 for psychosis. Two-point linkage analysis performed on a series of 52 multiplex pedigrees with 23 polymorphic markers yielded a LOD score of 2.02 at D18S37. An independent set of 159 parent offspring trios was used to confirm this suggestive finding. The TDT analysis yielded support for association between the marker D18S453 and the disease allele (chi2 = 4.829, P < 0.028). This region has been implicated by several studies on BPD [Sjoholt et al. (2004); Mol Psychiatry 9(6):621-629; Washizuka et al. (2004); Biol Psychiatry 56(7):483-489; Pickard et al. (2005); Psychiatr Genet 15(1):37-44], SCZ [Kikuchi et al. (2003); J Med Dent Sci 50(3):225-229; Babovic-Vuksanovic et al. (2004); Am J Med Genet 124(3):318-322] and also as a shared region between the two diseases [Ishiguro et al. (2001); J Neural Transm 108(7):849-854; Reyes et al. (2002); Mol Psychiatry 7(4):337-339; Craddock et al. (2005); J Med Genet 42(3):193-204]. Our findings provide an independent validation of the above reports, and suggest the presence of susceptibility loci for psychoses in this region.

Prevention of Pediatric Bipolar Disorder: Integration of Neurobiological and Psychosocial Processes

Bipolar disorder (BD) is a prevalent condition in the United States that typically begins before the age of 18 years and is being increasingly recognized in children and adolescents. Despite great efforts in discovering more effective treatments for BD, it remains a difficult-to-treat condition with high morbidity and mortality. Therefore, it appears prudent to focus energies into developing interventions designed to prevent individuals from ever fully developing BD. Such interventions early in the development of the illness might prevent inappropriate interventions that may worsen or hasten development of BD, delay the onset of first manic episode, and/or prevent development of full BD. Studies of populations at high-risk for BD development have indicated that children with strong family histories of BD, who are themselves experiencing symptoms of attention-deficit/hyperactive disorder (ADHD) and/or depression or have early mood dysregulation, may be experiencing prodromal states of BD. Understanding the neurobiological and genetic underpinnings that create risk for BD development would help with more accurate identification of this prodromal population, which could then lead to suitable preventative interventions. Such interventions could be pharmacologic or psychosocial in nature. Reductions in stress and increases in coping abilities through psychosocial interventions could decrease the chance of a future manic episode. Similarly, psychotropic medications may decrease negative sequelae of stress and have potential for neuroprotective and neurogenic effects that may contribute to prevention of fully expressed BD. Further research into the biologic and environmental mechanisms of BD development as well as controlled early intervention studies are needed to ameliorate this significant public health problem.

Variations in the vesicular monoamine transporter 1 gene (VMAT1/SLC18A1) are associated with bipolar i disorder

The vesicular monoamine transporter 1 gene (VMAT1/SLC18A1) maps to the shared bipolar disorder (BPD)/schizophrenia (SZ) susceptibility locus on chromosome 8p21. Vesicular monoamine transporters are involved in transport of monoamine neurotransmitters which have been postulated to play a relevant role in the etiology of BPD and/or SZ. Variations in the VMAT1 gene might affect transporter function and/or expression and might be involved in the etiology of BPD and/or SZ. Genotypes of 585 patients with BPD type I and 563 control subjects were obtained for three missense single nucleotide polymorphisms (SNPs) (Thr4Pro, Thr98Ser, Thr136Ile) and four non-coding SNPs (rs988713, rs2279709, rs3735835, rs1497020). All cases and controls were of European descent. Allele frequencies differed significantly for the potential functional polymorphism Thr136Ser between BPD patients and controls (p=0.003; df=1; OR=1.34; 95% CI: 1.11-1.62). Polymorphisms in the promoter region (rs988713: p=0.005, df=1; OR=1.31; 95% CI: 1.09-1.59) and intron 8 (rs2279709: p=0.039, df=1; OR=0.84; 95% CI: 0.71-0.99) were also associated with disease. Expression analysis confirmed that VMAT1 is expressed in human brain at the mRNA and protein level. Results suggest that variations in the VMAT1 gene may confer susceptibility to BPD in patients of European descent. Additional studies are necessary to confirm this effect and to elucidate the role of VMAT1 in central nervous system physiology.

Longitudinal stability of the CBCL-juvenile bipolar disorder phenotype: A study in Dutch twins

BACKGROUND

The Child Behavior Checklist-juvenile bipolar disorder phenotype (CBCL-JBD) is a quantitative phenotype that is based on parental ratings of the behavior of the child. The phenotype is predictive of DSM-IV characterizations of BD and has been shown to be sensitive and specific. Its genetic architecture differs from that for inattentive, aggressive, or anxious-depressed syndromes. The purpose of this study is to assess the developmental stability of the CBCL-JBD phenotype across ages 7, 10, and 12 years in a large population-based twin sample and to examine its genetic architecture.

METHODS

Longitudinal data on Dutch mono- and dizygotic twin pairs (N = 8013 pairs) are analyzed to decompose the stability of the CBCL-JBD phenotype into genetic and environmental contributions.

RESULTS

Heritability of the CBCL-JBD increases with age (from 63% to 75%), whereas the effects of shared environment decrease (from 20% to 8%). The stability of the CBCL-JBD phenotype is high, with correlations between .66 and .77 across ages 7, 10, and 12 years. Genetic factors account for the majority of the stability of this phenotype. There were no sex differences in genetic architecture.

CONCLUSIONS

Roughly 80% of the stability in childhood CBCL-JBD is a result of additive genetic effects.

Neuropsychological functioning in adolescent children of mothers with a history of bipolar or major depressive disorders

BACKGROUND

Growing evidence demonstrates an association of neuropsychological deficits with mood disorders, but it is not yet clear whether these deficits are risk factors or are concomitant with the symptoms. This study examines the neuropsychological functioning of a group of adolescent offspring who are at risk for a mood disorder by virtue of being raised by mothers who have been diagnosed with major depressive disorder (MDD) or bipolar disorder (BPD).

METHODS

Adolescent offspring of mothers with BPD (n = 43) or MDD (n = 72) and of psychiatrically well parents (n = 50) completed a battery of neuropsychological tests to assess executive functioning, memory, and attention.

RESULTS

Children of mothers with BPD showed deficits in executive functioning and selective deficits in spatial memory and attention, in comparison with children of well mothers. Deficits were not found for children of MDD mothers.

CONCLUSIONS

Knowledge of these neurocognitive processes could aid ultimately in determining whether neurocognitive deficits precede BPD, whether unique profiles are associated with various types of mood disorders, and who may benefit from interventions.

Sex differences in the familial transmission of mood disorders

BACKGROUND

Mood disorders exhibit familial transmission due to both environmental and genetic risk factors. Mood disorders are more common in women, yet the role of gender in the familial transmission of mood disorders is unclear. This study examines rates of mood disorder transmission to offspring based on the sex of affected parent, sex of offspring and role of clinical factors, such as childhood abuse history, comorbid psychiatric disorders, and traits of aggression and impulsivity.

METHODS

Risk of transmission of mood disorder to offspring from females and males was compared in a sample of 272 probands with a major mood disorder using generalized estimating equations (GEE). Demographic and clinical characteristics of all male and female probands were compared. Characteristics that differed in probands were entered into the model to obtain an unbiased test of gender differences in transmission rate. Multivariate GEE models, one for male probands and one for female probands, were used to test for risk factors in transmission of mood disorder.

RESULTS

Familial transmission rate of mood disorders from female probands was almost double that of males. There was no difference in transmission to male or female offspring. For male probands, offspring mood disorder was independently associated with earlier age of proband mood disorder onset, greater number of proband years ill, and proband history of childhood abuse. For female probands, offspring mood disorder was associated with higher aggression scores in probands.

LIMITATIONS

We did not directly interview offspring and also had limited data on psychopathology in co-parents. This is a cross-sectional study and cannot account for emergence of illness in offspring in the future.

CONCLUSIONS

The two-fold higher rate of maternal transmission of mood disorder may reflect differences in regulation of maternal and paternal transmission of mood disorder. Future studies need to determine the relative contribution of genetic and non-genetic factors and identify the factors responsible for higher rates of transmission of mood disorders by females with a mood disorder.

Genome-wide scan for genes involved in bipolar affective disorder in 70 European families ascertained through a bipolar type I early-onset proband: supportive evidence for linkage at 3p14

Preliminary studies suggested that age at onset (AAO) may help to define homogeneous bipolar affective disorder (BPAD) subtypes. This candidate symptom approach might be useful to identify vulnerability genes. Thus, the probability of detecting major disease-causing genes might be increased by focusing on families with early-onset BPAD type I probands. This study was conducted as part of the European Collaborative Study of Early Onset BPAD (France, Germany, Ireland, Scotland, Switzerland, England, Slovenia). We performed a genome-wide search with 384 microsatellite markers using non-parametric linkage analysis in 87 sib-pairs ascertained through an early-onset BPAD type I proband (AAO of 21 years or below). Non-parametric multipoint analysis suggested eight regions of linkage with P-values<0.01 (2p21, 2q14.3, 3p14, 5q33, 7q36, 10q23, 16q23 and 20p12). The 3p14 region showed the most significant linkage (genome-wide P-value estimated over 10 000 simulated replicates of 0.015 [0.01-0.02]). After genome-wide search analysis, we performed additional linkage analyses with increased marker density using markers in four regions suggestive for linkage and having an information contents lower than 75% (3p14, 10q23, 16q23 and 20p12). For these regions, the information content improved by about 10%. In chromosome 3, the non-parametric linkage score increased from 3.51 to 3.83. This study is the first to use early-onset bipolar type I probands in an attempt to increase sample homogeneity. These preliminary findings require confirmation in independent panels of families.

A prospective high-risk study of the association among maternal negativity, apparent frontal lobe dysfunction, and the development of bipolar disorder

In a previous paper, the authors found that impairment on the Wisconsin Card Sorting Test (WCST) in adolescence was predictive of bipolar disorder in young adulthood among offspring of mothers with bipolar illness. In the present study, the authors explore the contribution of maternal characteristics, beyond maternal mood disorder, to the prediction of offspring dysfunction on the WCST. Results showed that maternal bipolar disorder and maternal negativity were both predictive of impaired performance on the WCST during adolescence. The contribution of maternal negativity to offspring WCST impairment was not better explained by maternal personality disorder, mother's functional impairment, family loading for bipolar disorder, or offspring disruptive behavioral disturbance. Findings did not support a moderator model. However, support was found for a mediation model in which maternal negativity contributed to risk for offspring bipolar disorder through its negative association with apparent frontal lobe functioning, as measured by the WCST. Findings are discussed from the perspective of a vulnerability-stress model. In addition, the authors consider the possibility that maternal negativity and offspring impairment on the WCST may be reflective of a common heritable trait.

The CBCL predicts DSM bipolar disorder in children: a receiver operating characteristic curve analysis

BACKGROUND

No clear consensus has been reached yet on how best to characterize children who suffer from pediatric bipolar disorder (PBD). The CBCL-PBD profile on the Child Behavior Checklist (CBCL) has been consistently reported showing deviant findings on the Attention Problems, Aggressive Behavior, and Anxious-Depressed subscales.

AIM

To examine the sensitivity and specificity of the proposed CBCL-PBD profile for determining DSM diagnosis of PBD.

METHODS

We applied receiver operating characteristic (ROC) curve analysis to data from 471 probands from two family studies of attention-deficit hyperactivity disorder and their 410 siblings.

RESULTS

The CBCL-PBD score demonstrated an area under the curve (AUC) of 0.97 for probands and 0.82 for siblings for current diagnosis of PBD, suggesting that the CBCL-PBD provided a highly efficient way of identifying subjects with a current diagnosis of PBD in this sample.

CONCLUSIONS

These findings suggest that the CBCL-PBD may provide a highly efficient way of screening for childhood bipolar disorder.

Early symptoms of mania and the role of parental risk

OBJECTIVES

The objectives of this study were to: (i) describe the phenomenology of youths diagnosed with subsyndromal bipolar disorders; (ii) describe the phenomenology of youngsters who are the children of bipolar parents, who are also experiencing subsyndromal symptoms of bipolar disorder (patients with 'cyclotaxia'); and (iii) explore which symptoms may be most useful in identifying youths with cyclotaxia.

METHODS

Four hundred outpatients between the ages of 5 and 17 years received a diagnostic assessment and psychometric questionnaires pertaining to mood symptomatology and psychosocial functioning. Parental diagnostic information was also obtained. Children and adolescents were assigned to one of three diagnostic groups: a 'syndromal bipolar disorder (BP)' group (n = 118), a 'sub-syndromal bipolar (SUB-BP)' group (n = 75), or a 'non-bipolar (NON-BP)' group (n = 207). In addition, based on parental diagnoses, youths were assigned to either a high genetic risk group (n = 167) or a low genetic risk group (n = 233).

RESULTS

Youths with subsyndromal bipolar disorders were found to have intermediate degrees of manic symptoms than youths with bipolar disorder and youths without a bipolar diagnosis. Offspring of parents having a bipolar disorder were more likely to show symptoms of hypomania and mania than youths without a bipolar parent. Youths at genetic risk for developing a bipolar disorder were not found to be at higher risk for having a diagnosis of attention-deficit hyperactivity disorder or a disruptive behavior disorder. Finally, results suggest that elevated mood with irritability and rapid mood fluctuations are the key distinguishing characteristics of 'cyclotaxia'.

CONCLUSIONS

There exists a group of youngsters who are the offspring of a parent/parents with a bipolar disorder who do not suffer from BP 1 or BP 2, yet have elevated mood symptoms and psychosocial dysfunction. As a result of these observations, treatment studies are needed for youths with 'cyclotaxia'.

Family, twin, adoption, and molecular genetic studies of juvenile bipolar disorder

Juvenile bipolar disorder (JBD) has been a subject of significant research and debate. Phenotypic differences between JBD and adult-onset bipolar disorder have led researchers to question whether or not similar neuropathologic mechanisms will be found. While much is known about the genetic and environmental contributions to the adult-onset phenotype, less is known about their contributions to JBD. Here, we review family, twin, adoption, and molecular genetic studies of JBD. Behavioral genetic data suggest both genetic and environmental contributions to JBD, while molecular genetic studies find linkage to age of onset of bipolar disorder to chromosomes 12p, 14q, and 15q. Additionally, changes associated with symptom age of onset have been recently reported in the brain-derived neurotrophic factor (BDNF) and glycogen synthase kinase 3-beta (GSK3-beta) genes. We contend that further progress in discovering the precise genetic and environmental contributions to JBD may depend on advances in phenotypic refinement, an increased appreciation of comorbid conditions, and more investigation of the longitudinal course of the disorder.

Combined analysis from eleven linkage studies of bipolar disorder provides strong evidence of susceptibility loci on chromosomes 6q and 8q

Several independent studies and meta-analyses aimed at identifying genomic regions linked to bipolar disorder (BP) have failed to find clear and consistent evidence of linkage regions. Our hypothesis is that combining the original genotype data provides benefits of increased power and control over sources of heterogeneity that outweigh the difficulty and potential pitfalls of the implementation. We conducted a combined analysis using the original genotype data from 11 BP genomewide linkage scans comprising 5,179 individuals from 1,067 families. Heterogeneity among studies was minimized in our analyses by using uniform methods of analysis and a common, standardized marker map and was assessed using novel methods developed for meta-analysis of genome scans. To date, this collaboration is the largest and most comprehensive analysis of linkage samples involving a psychiatric disorder. We demonstrate that combining original genome-scan data is a powerful approach for the elucidation of linkage regions underlying complex disease. Our results establish genomewide significant linkage to BP on chromosomes 6q and 8q, which provides solid information to guide future gene-finding efforts that rely on fine-mapping and association approaches.

The ecology of bipolar disorder: the importance of sleep

Although much of the emphasis in treating Bipolar Disorder patients is on pharmacotherapy, sleep loss is an important trigger for mania and plays an important role in the condition. The purpose of this paper is to fully explore the chronobiological, environmental, social, and genetic factors that contribute to the sleep disruption that is characteristic of mania and bipolar disorder. This review is important because sleep, chronobiology, and genetics are under-emphasized content areas in nursing education. As a result, many practicing nurses are unaware of the importance of sleep for mental health or what to teach patients to improve both the quality of their sleep and the management of their condition.

Behavioral and cognitive profile of mice with high and low exploratory phenotypes

Temperament is the heritable and relatively stable pattern of basic emotions, such as fear and anger. We explored behavioral features in mice to select distinct phenotypes with extremes of temperament. In a new environment (open-field) with a central object, two groups of 15 mice from 79 screened were separated according to high or low exploration of the object to compose the high and low exploratory groups, respectively. Their performance was mostly identical in the same task 1 week later and still distinguishable 8 months later, suggesting the presence of trait or temperamental features. These mice were further tested in other behavioral tasks. Compared to low exploratory mice, high exploratory mice were less anxious in the light/dark task and the elevated plus maze, showed increased locomotion in an open-field, improved their performance along trials in the Lashley maze (with appetitive stimulus) and had higher latency to step-down in the inhibitory avoidance task (with aversive stimulus). High exploratory mice were aggressive in the intruder test, whereas low exploratory mice were non-aggressive or submissive. These results show that individual differences in temperament influence a range of behaviors in mice. The behavioral profile of low and high exploratory mice resembled the depressive and hyperthymic temperaments of patients with unipolar depression and bipolar disorders, respectively, which may be relevant for modeling mood disorders.

Epidemiology of bipolar disorders

Bipolar, or manic-depressive, disorders are frequent and severe mental illnesses associated with considerable morbidity and mortality. Epilepsy and bipolar disorder could probably share some aspects of pathophysiology because manic as well as depressive symptoms are seen in patients with seizures, and a number of antiepileptic drugs are effectively used in the acute and prophylactic treatment of bipolar disorder. Epidemiologic research suggests a dimensional composition of bipolar illness at the population level. Apart from the DSM-IV diagnostic features of bipolar I (mania and depression) and bipolar II (hypomania and depression), the concept of bipolar spectrum disorders comprises a range of bipolar conditions with less obvious manifestations with estimated lifetime prevalence rates ranging from 2.8 to 6.5%. Expanding the definition of bipolar II disorders shows that half of the patients currently diagnosed with a unipolar depressive episode could suffer from unrecognized bipolar II disorder, and about the same number of mild depressive patients could be minor bipolars. Research efforts to refine the diagnostic criteria of bipolar disorder aim at an earlier and complete recognition of the disease to provide appropriate pharmacological and nonpharmacological treatment early in the course of the illness to anticipate individual suffering, suicidal behavior, and increased socioeconomic costs for society. This article also discusses risk factors, comorbid conditions, course of illness, as well as the individual and socioeconomic impact of bipolar disorders.

CONCLUSIONS

The findings suggest reconceptualizing bipolar illnesses as highly recurrent, malignant disorders that occur far more frequently than previously thought. Interdisciplinary knowledge transfer could help to increase our understanding of the pathophysiology of these disorders as well as provide grounds for better recognition and treatment of patients with manic and/or depressive symptoms.

Neuropsychological dysfunction in bipolar affective disorder: a critical opinion

Data from the imaging literature have led to suggestions that permanent structural brain changes may be associated with bipolar disorder. Individuals diagnosed with bipolar disorder display deficits on a range of neuropsychological tasks in both the acute and euthymic phases of illness, and correlations between experienced number of affective episodes and task performance are commonly reported. These findings have renewed interest in the neuropsychological profile of individuals with bipolar disorder, with deficits of attention, learning and memory, and executive function, asserted to be present. This paper critically reviews five different potential causes of neurocognitive dysfunction in bipolar disorder: (i) iatrogenic, (ii) acute functional changes associated with depression or mania, (iii) permanent structural lesions of a neurodegenerative origin, (iv) permanent structural lesions that are neurodevelopmental in origin, and (v) permanent functional changes that are most likely genetic in origin. Although the potential cognitive effects of residual symptomatology and long-term medication use cannot be entirely excluded, we conclude that functional changes associated with genetically driven population variation in critical neural networks underpin both the neurocognitive and affective symptoms of bipolar disorder. The philosophical implications of this conclusion for neuropsychology are briefly discussed.

Recent findings on the genetic basis of bipolar disorder

What began as a search for a specific gene for bipolar disorder has now become a search for multiple susceptibility genes as it has be-come clear that the genetic basis of bipolar disorder probably involves multiple genes interacting with each other and with environmental components in as-yet mysterious ways. This article reviews the most recent findings and the emerging picture in the genetics of bipolar disorder.

The potential impact of genetic counseling for mental illness

Mental disorders are relatively highly heritable, yet complex with important interactions between genetic risk and environmental factors in determining illness expression. Due to the high prevalence of these complex disorders, steady increase in knowledge about genetic contributions, and increasing public awareness, this area may come to represent a significant proportion of all genetic counseling. The potential impact of genetic counseling in mental illness is broad. As well as the conventional expectations, genetic counseling may have the positive outcomes of reducing the guilt, shame, and stigma associated with mental illness, even within families. However, like many interventions in medicine, genetic counseling for mental disorders could potentially have unintended consequences resulting in increased stigma, guilt, and shame. The potential impacts of genetic education and providing recurrence risks on stigma are reviewed, as well as the role of education about the environment as a way of modifying family members' guilt. The review allows a preliminary formulation of a series of suggestions for genetic counseling in mental illness.

Genomewide scan for affective disorder susceptibility Loci in families of a northern Swedish isolated population

We analyzed nine multigenerational families with ascertained affective spectrum disorders in northern Sweden's geographically isolated population of Vasterbotten. This northern Swedish population, which originated from a limited number of early settlers approximately 8,000 years ago, is genetically more homogeneous than outbred populations. In a genomewide linkage analysis, we identified three chromosomal loci with multipoint LOD scores (MPLOD) >/=2 at 9q31.1-q34.1 (MPLOD 3.24), 6q22.2-q24.2 (MPLOD 2.48), and 2q33-q36 (MPLOD 2.26) under a recessive affected-only model. Follow-up genotyping with application of a 2-cM density simple-tandem-repeat (STR) map confirmed linkage at 9q31.1-q34.1 (MPLOD 3.22), 6q23-q24 (MPLOD 3.25), and 2q33-q36 (MPLOD 2.2). In an initial analysis aimed at identification of the underlying susceptibility genes, we focused our attention on the 9q locus. We fine mapped this region at a 200-kb STR density, with the result of an MPLOD of 3.70. Genealogical studies showed that three families linked to chromosome 9q descended from common founder couples approximately 10 generations ago. In this approximately 10-generation pedigree, a common ancestral haplotype was inherited by the patients, which reduced the 9q candidate region to 1.6 Mb. Further, the shared haplotype was observed in 4.2% of patients with bipolar disorder with alternating episodes of depression and mania, but it was not observed in control individuals in a patient-control sample from the Vasterbotten isolate. These results suggest a susceptibility locus on 9q31-q33 for affective disorder in this common ancestral region.